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By P. Mühlen, C. Nelson

Process control optimisation depends a lot on the availability of timely data from production to give operators a chance to make adjustments before potential process upsets or disruptions happen. A lot of data is already available with newer and updated machine technologies, but what about the process upsets coming from the raw materials that we use? They are natural products and therefore they are not of a stable composition or mineralogy. The production process depends on a certain chemical or mineralogical stability of the raw materials when they come to a roaster, kiln or sintering stage. Only then can the proposed reactions take place and the equipment be operated at stable temperatures. Laboratory analytical technologies have the limitation that they depend on representative samples and have a long time delay. Therefore online (real time) analysers are used nowadays in mining applications to obtain an early indication of the actual mined or to-be-processed ore. Most available technologies can only analyse inorganic content on an oxide or elemental level. Near infrared (NIR)- based online analysers can overcome that limitation and give a real time analysis of organic as well as inorganic composition, if required on a mineral level. The paper will present two case studies where the NIR online technology was successfully adapted.: a) Optimising refractory gold ore processing at the Goldstrike roaster operation b) Optimising the sinter process at a Japanese manufacturer. Keywords: Analyser, NIR, online, realtime, gold, roaster, iron ore, sinter, mineral phase analysis

Jan 1, 2020

By S. Kirkpatrick, J. Mukendwa

"The mining operation at Namdeb’s Southern Coastal Mine (SCM) is unique. It targets gravel layers up to 30 m below sea level, which continue to dip deeper, further west, under the Atlantic Ocean. On this storm-dominated coastline, severe water seepage into mining areas, rugged orebody footwall characteristics, and highly variable resource grades all contribute to a challenging operational environment. Namdeb has a proud history of innovation, and as the mine progresses further westwards and associated technical and economic challenges increase, this innovative culture has become essential to the future of the mine. The Theory of Constraints (ToC) has been widely used at SCM, and across the mining discipline, to focus efforts on improving overall business profitability. Through analysis of the mining processes, opportunities were identified, solutions developed, and initiatives implemented with staggering results across all three mining disciplines, i.e. stripping, load and haul, and bedrock bulking and cleaning. This paper outlines the solutions adopted and the results of the ToC analysis. IntroductionSouthern Coastal Mine (SCM) is one of three Namdeb operations located in the southwestern corner of Namibia, between the Orange River in the south, the Namib Desert to the east and the Atlantic Ocean to the west (Figure 1). These three geographical features set the backdrop for the world’s greatest marine diamond mining placer (Badenhorst, 2003). SCM is situated along the coastline extending from the mouth of the Orange River to Chameis Bay approximately 120 km to the north. The active mining area, called Mining Area 1 (MA1) is, however, limited to very narrow strip, 30 km in length, in the south of the licence area, close to the town of Oranjemund.Namdeb, a wholly owned subsidiary of Namdeb Holdings, is a 50/50 joint venture between De Beers and the Government of Namibia. Diamonds were first discovered along the Namibian coastline in April 1908, close to the town of Luderitz, but mining operations started in the SCM mining area only in February 1929 (Schneider, 2009). Initially all Namdeb mining operations exploited massive land-based deposits, producing nearly 40 million carats from MA1 between 1920 and 1977 (Schneider, 2009) when mining targeted onshore raised beaches west of the high water line. Since 1977 however, SCM and Namdeb have developed a unique mining method to economically extract the resource which extends westward under the Atlantic Ocean."

Feb 1, 2019

By D. G. Wymer, A. G. du Plessis, N. C. Joughin

The use of a dense hangingwal-support configuration extending right up to the face would enable greater levels of safety and productivity to be achieved in stopes, and becomes a practical proposition if water jets are used for stope cleaning. Such an arrangement opens the way for extending the use of water hydraulic power to the whole stoping operation. This, in turn, can provide further productivity benefits and significant savings in working costs. With al the necessary equipment being available, such a system could be introduced immediately, although the designs of props and rockdrills are not yet ideal.

Jan 1, 1989

By S. J. Webber

This paper reports on the use of the MINSIM-D stress-analysis program for the modeling of two large seismic events that occurred on the same fault eleven years apart. It was found that the first event (magnitude 5,2) could not be ascribed to purely mining-induced stresses, indicating that the largest seismic events probably result from the interaction of mining-induced stresses with large scale tectonic stresses. However, the stress changes induced during eleven years of mining were found to be capable of generating sufficient excess shear stress (ESS) to be responsible for the second event (magnitude 4,3), The upper limit for the magnitude of purely mining-induced events was found to be approximately 4,3.

Jan 1, 1990

By J. Petersen, H. Naderi, H. Zare, M. H. Nikzad, M. Karimi

In the copper electrorefining process, the dissolution of anodes is significantly reduced or even stopped when the passivation phenomenon occurs. The results of this phenomenon are increasing energy consumption, residual formatting, and voltage levels in the cell. In this study, the electrochemical behaviour of blister copper in the presence of sodium persulfate (PDS) was studied. The electrochemical methods of LPR, Tafel, and Electrochemical Impedance Spectroscopy (EIS) were used. The results showed that the addition of sodium persulfate activates the electrode surface and increases the open circuit potential. In the presence of PDS, the polarisation resistance of the electrode shows an increasing or decreasing tendency, based on the PDS concentration. This tendency is probably due to the formation of surface layers (such as slime layer or copper sulfate) and dissolution of this layer at various concentrations of PDS. The lowest polarisation resistance of 1.8 ohms and the highest corrosion current of 60.6×10-3 and 36.6×10-3 A/cm2 from LPR and Tafel techniques respectively were obtained at the concentration of 40 g/l PDS. Based on the results of potentiodynamic and electrochemical impedance spectroscopy tests, the addition of sodium persulfate to the solution reduces the corrosion resistance, therefore the passivation time of the blister copper anode increases. Keywords: Blister copper, electrorefining, sodium persulfate, anodic passivation

Jan 1, 2020

By A. Mainza

It is common practice in the mineral processing industry to use hydrocyclones for particle classification. However, classification in the UG2 platinum circuits using the hydrocyclone poses major challenges due to the differences in density between silica and chromite, the two major components of this ore. Silica,-the PGM carrying component, has an average density of 2.7 and the barren chromite component has an average density of 4.5. When conventional and flat bottom cyclone are used there is a misplacement of particles due to differences in density leading to inefficiencies in the classification by size. As a result of the density effect, coarse silica reports to the overflow, resulting in loss of recovery, and fine chromite reports to the underflow, resulting in loss of milling capacity and unnecessary production of fine chromite. A classifier based on a different concept was required in the classification of UG2platinum ore. The three-product cyclone, which is a hydrocyclone with two concentric vortex finders to produce three distinct products, has been tested in the UG2 ore application and indications are that misplacement of particles due to differences in the component densities can be minimized through the use of this unit. Industrial and pilot plant trials were conducted and indications are that the three-product cyclone can be installed to selectively produce a middlings stream that can be screened using Pansep screens to provide a screen oversize, which is predominantly coarse silica that can be preferentially reground to recover the PGM values contained in the coarse silica.

Jan 1, 2004

By D. G. Krige

The problem of a realistic investment analysis for a new mining venture that sells its products on the international metal markets IS studied against the background factors, firstly, of different inflation rates between the countries hosting the mines and those. hosting the metal markets; and, secondly, of the changing pattern of currency exchange rates between such countries. The purchasing-power parity theory is used to establish a pattern of relationship between these two factors, and to develop a more logical approach to the long-term forecasting of metal prices in the currency of the country in which the mine is situated.

Jan 1, 1979

To be held from the 9th to 14th April, 1972, in Johannesburg, South Africa. GENERAL INFORMATION The first symposium in the series was staged by the University of Arizona in 1961. Since then Stanford University, Colorado School of Mines, Pennsylvania State University and the Society of Mining Engineers of the American Institute of Mining, Metallurgical and Petroleum Engineers have acted together with the University of Arizona as co-sponsors of the series. The 9th Symposium in 1970 was sponsored by the Canadian Institute of Mining and Metallurgy together with McGill University and Ecole Poly technique in Montreal. The 10th Symposium, the first to be held outside the North American continent, is being organised by the South African Institute of Mining and Metallurgy (with the Council for Scientific and Industrial Research and the South African Council for Automation and Computation) in close collaboration with the previous co-sponsors. OBJECTIVES Mineral ventures increase in scale and complexity. The planning and control of these projects requires more and more sophisticated techniques. The intention of the symposium is to pool and exchange experience and knowledge and also to discuss new and potential developments. The papers presented in the main sessions, which will extend over one week, will together indicate progress which has been made in the successful application of operations research, mathematical, statistical and computer methods in each of the various aspects of operation in the mineral industry. A coherent account will be developed by consideration, in consecutive sessions, of the stages through which mineral prospects evolve in the course of their life. Primary aims are thus to stimulate discussion in depth of previous applications, to highlight current trends and to provide guidelines for future developments. PARTICIPATION The intention is to bring together persons responsible for managing the various operations in the mineral industry and the workers engaged in the development of mathematical and computer methods relevant thereto. SYMPOSIUM TOPICS 1. Market Analysis-demand and supply trends, models of mineral markets, price prediction. 2. Exploration and ore reserve estimation--exploration strategies, choice of drilling and sampling patterns, quantification of geological information, geo-statistical analysis, ore reserve assessment. Storage and retrieval of associated data. 3. Project design and analysis-influence on viability and risk of capitalisation, scale and method of operation, processing, uncertainties in design premises. 4. Planning of operation-planning and scheduling of construction, of development and of depletion of ore reserves. Logistics, rock mechanics and ventilation. 5. Control of operations-financial, production, cost and quality control as applied to both mining and processing. Flow and processing of relevant information. CALL FOR PAPERS An invitation is extended to intending authors to submit a synopsis, in 200 to 300 words, of papers which would develop the themes outlined above. The Programme Sub-Committee will choose, on the basis of these synopses, some 20 to 30 authors who will be invited to submit papers. Selection will be aimed at the provision of a coherent structure. Other authors may be invited to submit short papers either as contributions to the primary papers or for brief discussion in ancillary sessions which will be scheduled to follow on the main sessions. The official language of the symposium will be English. DEADLINES Prospective authors must submit synopses of papers by ............end April, 1971 Authors will be informed of results of selection of papers by . . . . . . . end June, 1971 Manuscripts will have to be in the hands of the Editors by . . . . . . . . . end October, 1971 PRE-PRINTS Papers selected for presentation in the main sessions will all be pre-printed and distributed prior to the symposium. As many as possible of the shorter papers and prepared contributions will also be pre-printed. PROCEEDINGS All of the main and ancillary papers together with edited discussion will be published shortly after the symposium in a single volume. TOURS AND VISITS A choice of visits to relevant local undertakings on a day during the course of the symposium will be available to participants. These will include a deep level gold mine. A tour which will include mineral projects of interest and the Kruger National Game Park will be arranged in the week following the symposium. LADIES' PROGRAMME Arrangements will be made for the reception and entertainment of ladies. ACCOMMODATION Accommodation will be available at hotels convenient to the symposium venue. The cost of reasonable hotel accommodation in Johannesburg is in the range R5 to RIO (7 to 14 U.S. dollars) per person per night. All reservations and associated arrangements may be made through agents to be appointed by the organisers in due course. FEES AND COSTS Symposium fees will not exceed R70 (100 U.S. dollars). These will include registration, one copy of the published proceedings, a set of pre-prints of the main papers, teas and lunches during the course of the symposium, and the various official social events as well as the mid-week visits. Accommodation, travel and post-symposium tour charges are not included in this figure. FURTHER INFORMATION All communications should be addressed to: The Secretary, South African Institute of Mining and Metallurgy, Kelvin House, Hollard Street, Johannesburg, South Africa.

By M. Kannenberg

When coal properties are estimated geostatistically for mine planning in the hardcoal industry, there is one important supposition which influences the reliability of prediction of economically profitable parts of the deposit. This is the fact that activities in hardcoal exploration and mine planning are characterized by distinct levels of information and knowledge upon which decisions of economic import must be based, for example, whether exploration should proceed or not, or which methods and strategies should be used to maximize search efficiency. To get more reliable results for mine planning, in particular, advanced kriging methods (e.g. conditional simulation) have to be introduced and checked for their reliability in historical analyses (post-mortem studies). By using this feedback, kriging results from underground samples or production data can be compared with results gained by advanced geostatistical methods from exploration boreholes.

Jan 1, 1987

I am a partner in a minerals' development company called A.B.F. Limited, that does minerals development in Africa and Asia. I have read your very fine magazine often at the Colorado School of Mines Library in Golden, Colorado. I would like to ask your assistance in trying to locate a South African smelter; preferably on the coast, but not totally necessary for the project, that can separate the first four metals (Au, Ag, Cu, and Pb).

Jan 1, 1980

By E. J. Maunders

This paper describes briefly a computerised model of the South African electricity system which has been developed jointly by the Atomic Energy Board and the Electricity Supply Commission. The results of an analysis of this system have been subjected to a fairly extensive sensitivity analysis which reveals that up to the year 1990 between 680 and 700 million tons of coal will be required for electric power generation, together with between 7 000 and 10 000 tons of uranium. This result is fairly insensitive to data variations, but the prediction of a cumulative requirement up to the year 2000, of between 1 300 and 1 800 million tons of coal and 25000 to 70000 tons of uranium, proves to be very data-sensitive.

Ninth International Symposium TECHNIQUES FOR DECISION MAKING IN THE MINERAL INDUSTRY The Symposium which is to be held in Montreal during the week of 14th to 19th June, 1970, follows the Computer Symposium held in Salt Lake City in September, 1969. The purpose of the Symposium is to define the role of decision-making techniques within the mineral industry and to stimulate the development of specific applications. The subject of the Symposium-mathematics, operations research and computers as applied to the mineral industry-have permitted us to structure it in such a way that a complete picture of the mineral industry in its public policy, corporate, financial and technological environment emerges. Topics for the sessions are: . The Public Policy Environment;. The role of Decision Making Techniques in the Mining Company; . Information Storage and Retrieval; . Markets-Forecasting, Patterns and Strategies;. Search for Mineral Deposits;. Quantification of Geological Variables;. The Mine Development Decision; Production Systems;. Planning, Scheduling and Control Systems. The sessions will be directed energetically by chairmen who have been in continuous contact with the authors, providing them with information about related papers and sessions. This symposium is sponsored by the Canadian Institute of Mining and Metallurgy, McGill University and Ecole Polytechnique. Further information may be obtained from: The 9th International Symposium. W. H. Gauvin, General Chairman, J. Elbrond, Programme Chairman. Department of Mining Engineering, Ecole Poly technique, P.O. Box 501, Snowdon, Montreal 248, Quebec, Canada. ACHEMA 1970 The European meeting of Chemical Engineering and the Achema Congress 1970 is being held at Frankfurt/Maine, from 17th to 24th June, 1970. The programme includes some 110 plenary and specialised lectures, numerous technical films, excursions, and technical discussions in front of the exhibits which form the central feature of the Achema-Exhibition Congress. Further information may be obtained from the honorary representative of Achema in South Africa, Mr F. Schilling, P.O. Box 31274, Braamfontein, Johannesburg. NINTH COMMONWEALTH CONGRESS PROCEEDINGS Publication of the proceedings of the Ninth Commonwealth Mining and Metallurgical Congress, 1969, is being undertaken by the Institution of Mining and Metallurgy, London. There will be four volumes covering papers presented at the Congress together with the discussion and author's replies, and the addresses by Sir Duncan and Sir Ronald Prain. These will be available April-June 1970. Special pre-publication prices apply to orders received before 1st April, 1970. Order forms may be obtained from Secretary S.A.I.M.M., P.O. Box 1183, Johannesburg. 6th World Congress on the Prevention of Occupational Risks This Congress, dealing with industrial accidents and occupational diseases, will be held in Vienna from 10th to 15th May, 1971. Further information may be obtained from: VI Weltkongress für Unfallverhütung, Postfach 745, A-1015 Wien, ÖSTERREICH. International Vacuum Metallurgy Conference 1970 The Vacuum Metallurgy Division of the American Vacuum Society is organizing an international meeting that will be held at the Convention Center in Aanaheim, California from 15th to 19th June, 1970. Enquiries should be directed to the Arrangement's Chairman, L. M. Bianchi, TRW Inc., 23555 Euclid Avenue, Cleveland, Ohio 44117, Tel. No. (216) 383-2111. AIME WORLD LEAD-ZINC SYMPOSIUM This symposium is being held from 21st to 23rd October, 1970, in St. Louis, Missouri, U.S.A., in conjunction with the Fall Meeting of the Society of Mining Engineers, and a Rapid Excavation Conference. In addition to local field trips to smelter and refinery operations there will be a number of extended trips of six to eight days. Information may be obtained from: Mr. John C. Fox, Secretary, Society of Mining Engineers of AI.M.E., 354 East 47th Street, New York, N.Y. 10017, U.S.A. NEW SUBSCRIPTION RATE TO THE JOURNAL As from 1st JANUARY, 1970, the subscription rate for the Journal has been increased from R12.00 to R18.00 per annum, i.e. R1.50 per issue instead of R1.00. The discount to booksellers is 15 per cent. COURSEOF THE THEORYOF THE UNIT OPERATION OF GRINDING The South African Institute of Chemical Engineers is arranging for Prof. L. G. Austen to conduct a course on the above subject in September, 1970. Interested persons should contact Dr G. S. Harrison, S.A. Institution of Chemical Engineers, A.E. & C.I., 15 Anderson Street, Johannesburg. METRICATION The S.A. Bureau of Standards has published a document entitled "Metric Scales and Units for use in the Building and Construction Industry." It has been compiled by the Metrication Committee of the National Building and Construction Advisory Council and is the first of the series of informatory documents relating to the programme for the metrication of the Building Act Construction Industry. This document is obtainable from the South African Bureau of Standards, Private Bag 191, Pretoria at 50c per copy.

By W. T. Ruhmer

Slimes-dam construction in the gold mines of the Anglo American Group by w. T. RUHMER. Pr.Eng.. B.Sc. Eng. (Met.) (Fellow) Current practices generally in accordance with the principles of design and operation of slimes dams within the Gold Mining Division of the Anglo American Corporation are described. Although many of the details given are either obvious or have been amply dealt with elsewhere, these have been included for the sake of completeness. The selection of suitable ground for the deposition of slimes, the initial design and construction of a slimes dam, and its consequent operation are presented in logical sequence. Emphasis is placed on the code of practice for the construction of slimes dams issued by the Chamber of Mines of South Africa, and draft regulations (Water Act of 1956) dealing with pollution. Operating costs are included, and possible future trends are discussed.

Jan 2, 1974

By D. A. Vetter

A novel mathematical model is presented which describes the behaviour of beds of particles, of uniform size and shape but different densities, during autogenous separations. The approach used in the formulation of the dispersion model is a phenomenological one based on a statistical view, which leads to a diffusion-like representation of the autogenous-separation process. Although the model currently considers only density-related phenomena, it accounts quantitatively not only for the density-segregation aspects of the process but for the interactions between the particles. Quantitative predictions of the dispersion model are compared with the results obtained in tests using a specially constructed experimental batch jig, and it is shown that the model provides an adequate quantitative description of the process for particles of uniform size and shape. It is pointed out that, for the description of more complicated autogenous separations, a more rigorous formulation of the particle drag and density-segregation terms will have to be incorporated into the dispersion model. Nonetheless it is concluded that the model as presented in this paper provides not only a novel insight into the mechanisms of autogenous separations but a means by which to analyse similar systems.

Jan 1, 1987

By I. Zh. Bunin, M. V. Ryazantseva, V. A. Chanturiya

The paper proposes a new method for selective calciferous separation. The effect was achieved through the application of the combination of high-power electromagnetic pulses (HPEMP) and a specific reagent regime of the flotation. The combined application of HPEMP with the special reagent regime allowed for the improvement of the scheelite floatability: the recovery of CaWO4 rises from 41.2 % (untreated sample) to 58.5 (sample treated at 103 pulses). In contrast, the floatability of calcite decreases significantly: the recovery of calcite drops from 74.7% (untreated sample) to 41.1 % (sample treated at 103 pulses). The conditions were found for the selective separation of the minerals with very close flotation properties. Keywords: Calcite, scheelite, flotation, high-power electromagnetic pulses, DRIFT, XPS

Jan 1, 2020

By F. M. Ramadhan, M. R. Pratama

Monitoring open-pit mine road conditions has become very critical nowadays. There are several benefits to in conducting research on this field such as opportunity to improve truck’s speed which directly influences truck’s productivity. This research aims to provide a semi real-time, and sensors-based automatic road damage detector that predicts the road quality through road damage exact location tracing, road damages auto-classification, and real-time instruction in the form of work order format to mining road maintenance, and repair authorities through mobile apps and maintenance unit’s in-cabin display. It will also provide the maintenance/repair activity performance evaluation via integrated dashboards. The artificial neural network algorithm is applied during the process of data training regarding classifying road damages and severities which resulted in a valid model. The road damage classification model has a precision level of 80.5% in predicting whether the road is damaged or not. Using this approach, we are expecting to visualise a road quality map of all active roads on mine site.

Sep 1, 2021

By N. B. Prenn, R. H. Robinson

"The model described is a design and economic planning tool for analyzing surface mineral deposits. Mineralization, topography, costs and significant geologic features are input to the model. The results are:(i) final pit limits yielding the maximum total profit,(ii) annual cut-off grades and plant sizing yielding the maximum present value, and(iii) annual maps of the pit and annual production statistics for the mine, concentrator and smelter.Additionally, summaries are printed of the block mining sequence and cash flow. A special feature is an option to include dump-leaching operations. Stockpiling of material can also be simulated by the model. The model is built around theories of dynamic cut-off grades and a pit design algorithm. The dynamic cut-off grades maximize present value by examination of all economic and physical constraints for the optimum combination. The pit design algorithm is a set of rules formulated to find the maximum value from a special graph. The graph is different from graphs of analytical geometry, being made up of points and arrows connecting some of the points. These graph elements describe the relationship between any point in the deposit and the material which must be mined to get at that point. The model was designed to bring together the interdependent theories of economics, pit design and production scheduling."

Jan 1, 2014

By R. Kok, N. B. Strydom, P. L. Jooste, W. H. Van Der Walt

Intermittent exposures to heat, and the retention of heat acclimatization by N. B. STRYDOM, M.Sc., Ph.D. (Illinois) (Fellow), R. KOK, M.Sc. (Potch.) (Visitor), P. L. jOOSTE, M.Sc. (Stell.) (Visitor), and W. H. VAN DER WALT, B.Sc. (Potch.) (Visitor) Twenty-one heat acclimatized subjects were assessed for the degree of acclimatization attained with respect to heart rate, rectal temperature, and sweat rate during a standard four-hour heat-stress test. Thereafter, they were put on light duties in cool environm ents for four weeks, except for four hours of exposure to heat every seventh day. Their state of heat acclimatization was again assessed two days after the final week's exposure. Although heart rates and body temperatures showed significant increases over the initial values, no differences were observed in sweat rates and, in general, the subjects were rated as still adequately acclimatized to heat.

Jan 7, 1975

By Donald J. Murdock

Column flotation has been developed over the past ten years as an alternative to conventional flotation. It has been used mainly in the cleaning applications of sulphide flotation, where its ability to wash the froth of entrained gangue and produce a higher-grade product has given it a distinct advantage over other technology. The benefits of column flotation can be summarized as follows: Improved concentrate gradeby 2 to 5 per cent . Significantly lower operating costs . Savings in capital investment . Superior control. Since the initial development of the equipment, a number of design improvements have been developed that now form the basis of the Cominco column-cell design. The purpose of this article is to discuss some of those design innovations, and present some typical industrial results.

Jan 1, 1991

By A. J. S. Benade, A. J. A. Heyns, N. B. Strydom

The maximum oxygen intakes of samples of about 30 Bantu, weighing less than 50 kg from different tribal groups (Zulu, Xhosa, Sotho and Shangaan) were measured on a treadmill. The mean maximum oxygen intake of the 164 men was 2,12 litresjmin and only 18 men (11 per cent of the sample) had maximum oxygen intakes of 2,5 litres/min or above (the minimum requirement for such tasks as shovelling rocks and tramming it). The samples of the different tribes differ in age, but when the age effect is taken into account then there were no significant differences between tribes in maximum oxygen intakes. An incidental finding was that both age and body weight correlated significantly with the maximum oxygen intakes of these underweight subjects. Not one of the subjects who weighed less than 45 kg or who was older than 40 years had maximum oxygen intakes high enough to permit their being able to do strenuous work underground. It is clear therefore that Bantu who weigh less than 45 kg or are older than 40 years should not be employed on such strenuous tasks as shovelling rock and tramming it.